Drilling rigs often include a machine known as a drawworks or hoist for raising and lowering piping and drill bits. A typical drawworks includes drill line wound around a large drum or spool. The drill line extends from the drum through a pulley or other block and tackle arrangement to a travelling block. A drive system rotates the drum to reel in the drill line, and a brake lever may be manually operated to apply or release a brake connected to the drum. For example, the brake lever may be positioned to manually release the brake to allow the drive system to rotate the drum to reel in the drill line and raise the travelling block. Alternately, the drive system may be disconnected from the drum, and the brake lever may be positioned to manually release the brake to allow the weight of the travelling block to rotate the drum to release drill line from the drum and lower the travelling block.
The weight of the travelling block and drill pipe is typically hundreds of tons. As a result, the travelling block may cause substantial equipment damage and/or personnel injury if the travelling block were raised or lowered beyond established limits. Therefore, various safety devices, systems, and/or interlocks have been developed to prevent the travelling block from travelling beyond established limits. For example, U.S. Pat. No. 7,138,925 describes a control system that senses the position, movement, and/or rate of movement of the travelling block to automatically actuate the brake to prevent the travelling block from exceeding predetermined limits. Although effective at limiting movement of the travelling block, the automatic actuation of the brake may also rapidly and forcefully move the brake lever, causing surprise, personnel injury, and/or equipment damage for personnel or objects in the path of the brake lever. Therefore, a system and method for operating a brake lever that reduces or prevents surprise, personnel injury, and/or equipment damage would be useful.